Telemetric system



Oct. 23, 1951 HQRNFECK 2,572,481

TELEMETRIC SYSTEM Original Filed 001:. 25, 1947 Z2 W6 57 i i 58 5 5 6|6? it; 74 75 jl PHASE 78 I7 SENSITIVE RELAY m J l8 INVENTOR.

ANTHONY Jv HORNFECK transmitting and receiving mechanisms.

Patented Oct. 23, 1951 TELEMETRIC SYSTEIH Anthony J. Hornieck,Lyndhurst, Ohio, assignor to Bailey Meter Company, a corporation oiDelaware Original application October 25. 1947, Serial No.

782,114, now Patent No. 2,524,665, dated October 3, 1950. Divided andthis application April 22, 1950, Serial No. 157,555

7 Claims.

This invention relates to telemetric systems, and more particularly tosystems for transmitting signals in response to a variable andpositioning a receivin member by the signals at a remote point toprovide an indication or record of the variable.

A preferred form of my invention may include a transmitting mechanismoperating to produce a signal varying in response to a variable to bemeasured, and a receiving mechanism having a balanceable network whichis subjected to difl'erent unbalancing conditions during intervals oftime varying with the signals transmitted. The signal may be transmittedduring portions of fixed time intervals to produce a condition tendingto unbalance the network in one direction, and means may be provided toproduce another condition tending to unbalance the network in theopposite direction during the remainder of the time intervals. Ifdesired, the transmitter may produce different signals during theportions of the time intervals for creating difl'erent unbalancingconditions. The unbalancing efl'ect on the network is proportional tothe difl'erence between the products of the unbalancing conditions andthe intervals of time during which each is applied. Means responsive toan unbalance oi the network may be provided for rebalancing the latterand for positioning suitable indicating or recording means.

An object of my invention is to provide an improved telemetric system.Another object is to provide a telemetric system having improved Yetanother object is to provide a telemetric system which includes only apair of wires between a transmitter and a receiver, and which operatesto provide an indication or record at the receiver -oi' a variable bythe transmission of signals at low voltage over the pair of wires. Otherob- ,iects will appear in the course of the following description.

The single figure of the drawing is a schematic diagram of an improvedtransmitting mechanism adapted for use in a telemetering system of thegeneral type disclosed in my parent Patent No. 2,524,665 of which thisapplication is a division.

The transmitter includes transformers 55 and 56 having primary windings51 and 58 connected to a source of alternating current, and airingsecondary windings 60, ti and 62, 53 connected in a closed loop byconductors 64, 65. A core member 61 is arranged between the primary andsecondary windings of the transformer 55 and is connected to one end ofa pivoted member I which engages at its other end with a cam ll rotatedat a constant speed by a motor Ill. The cam 59 is shaped so as toreciprocate the core member 61 at a constant speed between the windingsof the transformer. Arranged between the primary and secondary windingsoi the transformer 56 is a core member I! which is connected to a device73. such as a Bourdon tube. responsive to some variable condition.Leading from the closed loop at points between the aiding secondarywindings are conductors 14 and I5 con nected to a phase sensitive relay16 like that disclosed in my application, 8. N. 633,891, iiled December8, 1945. This relay is of the electronic type and is operative at a verysmall voltage of a predetermined phase to move a contactor 18 intoengagement with a contact 19 for completing the circuit through theconductors I1 and II. The core member 12 may be considered as atransmitting member since the closing of contactor 18 to energize theconductors ll, It is determined by the position assumed by this member.

When the core members 81 and I2 are in the same positions with respectto the windings of their transformers. the voltages induced in thecorresponding secondary windings are equal and opposite so that thevoltage across the conductors l4, I5 is zero. 11' the core members aredisplaced irom each other in one direction. a voltage of a certain phaseexists across the conductnrs ll, 15, and the value of the voltage varieswith the amount of displacement. When the core members are displaced inthe opposite direction, a voltage opposite in phase to the first voltageexists across the conductors ll, 15. The range of reciprocation oi thecore member 51 should be adjusted so that its upper and lower limits areequal to or greater than the limits of the core member I2 on maximumchangs in the condition to be measured. The range or the core member 51may be determined by the size of the cam 55 and the location of thepivotal support for the member 6..

Assume that the core members are in the same positions with respect tothe windings of their transformers and that the core member 12 re- 7mains in this position while the core member 61 is reciprocated. A veryslight movement of the core member in one direction will produce avoltage of. a phase which operates the relay 18 to close the contactor15 with the contact 15. While the core member moves in this direction tothe end of its stroke and then returns to its initial position, thevoltase will continueto be of a phase to operate the relay. As soon asthe core member returns to its initial position the voltage acrossconductors 14, 15 becomes zero and the contactor 18 moves to its openposition. A movement of the core member to the other side of its initialposition results in a voltage opposite in phase to the first voltage,and the contactor I8 remains in its open position. If the core member 12is in a position mid-way between the positions it would assume at theopposite limits of the condition measured, and if the core member 61 isreciprocated between corresponding limiting positions, the distancestraveled by the core member 61 at opposite sides of the core I2 areequal and result in a holding of the contactor 18 open and closed equalintervals of time. A movement of the core member 12 from itsmid-position means that the core member 61 must move an equal amountfrom such position to reach a point from which it may travel in eitherdirection to produce voltages of diflerent phase. Since the core member61 will have a greater distance to travel in one direction than theother from its new position, the contactor 18 will be held open or c osd longer intervals of time.

Whil there is disc osed in this application one form which my inventionmay assume in practice it will be understood that it may be modified andembodied in various other forms without departing from its spirit or thescope of the appended cla ms.

This application is a division of my copending application S. N.782.114, filed October 25. 1947, now Patent 2.524.665 dated October 3,1950.

What I claim as new and desire to secure by United States Letters Patentis:

1. A mechanism for transmitting signals representative of a variablecondition including in combination. a closed loop circuit including twopairs of secondary transformer'windings, an energized primary windingfor each pair of secondary windings, means for increasing the fluxlinkage between each primary and a secondary of each pair and todecrease the flux linkage with the other secondary of each pair toproduce a net differential voltage across the two secondaries of eachpair whose magnitude is a linear function of the movement of the fluxlinkage means, means for uniformly varying the linkage between one setof primary and secondary windings within predetermined limits, means forvarying the linkage between the other set of primary and secondarywindings in response to changes in the variable to be measured, a phasesensitive device connected to said closed loop at points between the twosecondary windings of each included pair, and a circuit connected to asource of power and having a contactor controlled by said phasesensitive device.

2. A mechanism for transmitting signals representative of a variablecondition including in combination, two transformers each having aprimary winding and a pair of aiding secondary windings, means forenergizing said primary windngs, means for connectng said secondarywindings in a closed loop, means for variably flux-coupling the pri maryand secondary windings of each of said transformers, means for uniformlyvarying the coupling between one set of primary and secondary windingswithin predetermined limits, means for varying the flux-coupling betweenthe other set of primary and secondary windings in response to changesin the variable to be measured, a relay sensitive to the difference inoutput connected between the secondary windings of each of saidtransformers, and a circuit controlled by said re ay.

3. A mechanism for transmitting signals representative of a variablecondition including in combination, two transformers each having aprimary winding and a pair of aiding secondary windings, means forenergizing said primary windings, means for connecting said secondarywindings in a closed loop, a core member movable between the primary andsecondary windings of each of said transformers, means for reciprocatingone of said core members in a predetermined path, means for positioningthe other of said core members in response to changes in a variable tobe mea ured. a phase sensitive device connected to said losed loop atpoints between the two secondary windings of each of said transformers,and a circuit connected to a source of power and having a contactorcontrolled by said device.

4. A mechanism for transmitting signals representative of a variablecondition comprising, in combination, two transformers, each having aprimary winding and a pair of aiding secondary windings, means forconnecting said primary windings to a source of alternating current,means for connecting said secondary windings in a closed loop, coremembers movable between the primary and secondary windings of saidtransformers, means for positioning one of said core members in responseto a variable to be measured, means for reciprocating the other of saidcore members between points corresponding to the positions assumed bythe first core member at extreme values of said variable, a. phasesensitive device connected to said closed loop at diametrically oppositepoints, and a circuit connected to a source of power and having acontactor movable to open and closed positions under the control of saiddevice.

5. A mechanism for transmitting signals representative of a variablecondition comprising, in combination, two transformers, each having a,primary winding and a pair of aiding secondary windings, means forenergizing said primary windings, means for connecting said secondarywindings in a closed loop, core members movable between the primary andsecondary windings of said transformers, means for reciprocating one ofsaid core members in a predetermined path, means for positioning theother of said members in response to a variable to be measured, a phasesensitive relay connected to said closed loop at points between thesecondary windings of each of said transformers, and a circuit connectedto a source of power and having a contactor movable to open and closedpositions under the control of said relay.

6. A mechanism for transmitting signals representative of a variablecondition including in combination, two transformers each having aprimary winding and a pair of aiding secondary windings, means forenergizing said primary windings, means for connecting said secondarywindings in a closed loop, core members movable between the primary andsecondary windings, a cam operatively connected to one of said coremembers to move it in a predetermined path, a constant speed motor meansfor activating said cam uniformly that the core will reciprocate in thepath, means for positioning the other of said members in response to avariable to be measured, a phase sensitive relay connected tosaid closedloop at points between the secondary windings of each of saidtransformers, and a circuit connected to a source or power having acontactor 8 movable to open and closed positions under the control orsaid relay.

7. A telemetric transmitter for transmitting an electrical signalvarying in representation of a variable to be measured or transmitted,including in combination, two movable core transformers each having aprimary winding and a pair of secondary windings and a core movablerelative to the said windings for varying the flux linkage therebetween.a loop circuit including said secondary windings, a source ofalternating current for the primaries, means for cyclically positioningthe core of one transformer between predetermined limits, means forpositioning the core of the other transformer in accordance with thevariable, a phase sensitive device connecting the joining point of eachpair of secondaries in said loop circuit, and a relay controlled by thesaid device.

ANTHONY J. HORNFECK.

No references cited.

